3rd-year Post-surgical Evaluation of Adjacent Segment Disc Degeneration Onset in Lumbar Spine (Spinal Fusion vs. Lumbar Arthroplasty With Disc Replacement)

Inclusion Criteria: * All patients who have given written, informed consent. * All patients covered by a health insurance scheme. * All patients aged over 18. * All patients operated with a lumbar spine disk prosthesis or vertebral arthrodesis with an anterior approach at the Orthopedic, Traumatology and Spine Surgery Department of Nimes University Hospital, France, at least 3 years previously. * All patients who have undergone initial MRI before surgery. Exclusion Criteria: * Any patient taking part in a category 1 interventional study and in an exclusion period determined by a previous study. * Any patient under legal protection, guardianship or tutorship. * Any patient who refuses to sign the consent form. * Any patient for whom it is impossible to give clear information. * Any patient with contra-indications for Magnetic Resonance Imaging such as an incompatible pacemaker, claustrophobia, metal apparatus or prosthetic hip. * Any patient with a septic complication. * Any patient with instrumentation or posterior arthrodesis.